Connector switch



TIMER STARR IN V EN TOR.

PIER BAKKER I ATTORNEY July 21, 1953 P. BiAKKER CONNECTOR SWITCH 4 Sheets-Sheet '2 Filed 0G11. l, 1949` INVEITOR. PIER BAKKE ATTORNEY July 21', 1953 P. BAKKER 2,646,466

CONNECTOR SWITCH Filed '0017. 1, 1949 4 Sheets-Sheet 5 9.. v9 8" IN V EN TOR.

Ao T, T2144 Ao j?. ai; PIER BAKKER B B BY C CHI, No AIO July '21, 1953 P. BAKKER 2,646,466

CONNECTOR SWITCH Filed oct. 1, 1949 4 Sheets-Sheet 4 CONNECTOR SWITCH F l@ 4 JNVENTOR.

446 9 8 9 Pat-:R .BAKKER FIG. 7 v

Patented July 21, 1953 UNITED lSTATES ,ist

CONNECTOR sWrrorr Pier Bakker, Chicago, Ill., assignor to Automatic Electric Laboratories, Inc., Chicago, Ill., a corporation of Delaware Application October 1, 1949, Serial No. 119,082

Claims.

This invention relates to automatic telephone systems in general, and more particularly to small systems of the type commonly known as unat tended automatic community exchanges.

These systems as a rule are privately owned by individuals o-r small commercial groups and are installed in small communities, often rural, for providing local service between the local subscribers as well as connections overtrunk lines to other nearby communities and to a main oilice for long distance switching into the telephone companys network.

The object of this invention is to provide improved means employing a minimumamount of switching equipment to complete the desired connections and which is adapted to economical manufacture, yet provide all the features incumbent in a modern, high class, dependable wire communications system.

One of the features of this invention relates to marking means for marking on the connector switch the subscriber group desired by dialing the tens digit and for selecting the desired ringing code assigned to the desired party on the called line.

Another feature of the invention is that this same marking means is utilized for the marking a trunk call on the connector banks.

Still another feature of the invention is the utilization of this marking means for providing a common overow trunk for two trunk groups.

A further feature of this invention is provision for supervision available to a toll operator by a sixty interruption per minute flash busy.

lOther features, together with those hereinbefore recited will be fully explained hereinafter, reference being had to the accompanying drawings comprising Figs. 1 to 7 in which:

Fig. 1 shows the line equipment for one subscribers line with a plurality of parties thereon and the relation which such line equipment has to an eight-bank twenty ve-point rotary line iinder. The lower portion of Fig. 1 also shows an all-relay allotter for assigning the calls made to an idle finder-connector link of the system.

Figs. 2, 3 and 4 show the equipment making up part of one nder-connector link in conjunction with the line finder shown in Fig. l.

Fig. 4 shows the position of a two-bank tenpoint minor switch in a single finder-connector link, which switch is used to mark predetermined points on the connector banks as well as to select the ringing code for -a party line. Also shown in Fig. 4 is an eight-bank twenty-ve-'point rotary connector switch which taken in conjunction with theline inder in Fig. 1 relays in Figs. 2 and .3, and

relays and minor switch in Fig. 4 comprises one of the six nder-connector links in the system. At the extreme right in Fig. 4 is also shown the line equipment for two party lines.

Figs. 5 and 6 show two possible wiring arrangements of the rstvthree connector bank contacts accessible to wiper i136 for an overow trunk for a single and a multiple trunk group.

Fig. 7 is Ia wiring scheme of the rst three con* nector bank contacts of wiper ist providing a common overilow trunk for two-trunk groups.

The drawings, numbering four sheets and comprising Figs. 1 to 7 inclusive should be arranged with Fig. 1 to the left and Figs. 2, 3 and 4 in numerical order eachv to the right of the next lower in number, and when so arranged with corresponding lines of the various adjacent iigures in alignment, will diagrammatically disclose sufficient circuits and apparatus to enable `the in-Y vention to be understood in conjunction with the detailed description which follows.

Referring now to Fig. l, in brief, all subscribers, such as subscriber #231, `are equipped with a standard and well known monophone handset with dial. Each subscriber hasfa local line circuit, the conductors of which terminate in a finder bank. Each subscriber line has a linefrelay which operates responsive to removal of the handset from the cradle. The mechanism of the finders is of the well known rotary type, the wipers of which move around in a forward direction only and remain in the position last used. In the instant invention, the particular iinders depicted herein search for absence of ground, which condition also will occur responsive to raising the handset. Y n

The operationand circuit details of the rotary connectors are somewhat dierent from finders in that the wipers of theconnector are directively operated to a called line and are automatically restored to normal upon termination of the conversation.

In the case illustrated applicant has elected to show a system having a maximum of forty local lines having numbers, 2 iX to ZllX in the rst tens group, SiX to 39X in the second tens group, MX to MX in the third tens group, and 54X to 50X in the fourth tens group, inclusive, with 'provision for as many as ten parties per line, or a maximum of four hundred subscriber stations in all. The system vhas six allotter relays sequentially operated, of which there are three shown in Fig. l, to

allot predetermined ones .of the six iinder connector links available in the system. The` connector switches are shown in Fig. 4.

The system also provides six two-way trunks for 3 calls out of and into the local area served by this system. These trunks may be wired for overflow or one common trunk as an overow for two trunk ACertain relays in this system are two-step relays, such' as'200, 230, 200, 3|0, 330, 300, 310, 300 and k420, and operate their contacts marked X in their rst step and their remaining contacts in their second step. Relays |00, |30, |50, |60, 3|0 are slow-to-operate, and are also appreciably slow-to-release. Relays H0, 250, 3|0, 340 and 4|0 are equipped with copper sleeves around their cores rendering them slow-to-release but not slow-to-operate with the exception of relay 3|0 which because of its slug as well as its sleeve is both slow-to-operate and slow-to-release.

A minor switch of the well known type having an operating magnet and a release magnet is contained in each lnder-connector link as well as a number of marking relays, 300, 310, 380, 390, 400 and 420, which are responsive to diierent digits dialed into said minor switch. These relays in turn mark predetermined points on the Vconnector' switch banks so that the connector switch may step thereto and await thereon the next digit which is dialed directly to the stepping magnet of the connector. After the connector has thus functioned, a third digit determining the ringing code of a party on a party line is channelled to the minor switch.

The minor switch and marking relays operate similarly responsive to certain initial digits to mark a trunk or trunk group on the connector bank contacts assigned thereto.

Provision is also made by including X and Y leads for optional wiring if two-digit trunks are needed. By use of these leads properly wired, two-digit trunks are available. However, as will be described in detail hereinafter, they are wired to line bank contacts in the fourth tens group and correspondingly cut down the number of subscriber lines available in that group of the system.

Having brieily described the apparatus involved in a system of this type, a detailed description of the operation will now follow.

Local connection For this purpose, it will be assumed that subscriber 231 wishes to call subscriber 475. When subscriber 231 raises his handset to initiate the call, a circuit is completed through the loop from ground through induction coil ||1, contact H3, lower winding of line relay |740, contact |25, conductor |08, the Iconventional handset of calling subscriber 231, conductor |01, contact |24 and upper winding of line relay |40 to battery, energizing relay |40. Relay |40 operating; places ground upon the CN lead through contact |42, making this line busy to any incoming calls thereto on the connector banks; removes ground from the C lead by opening `contact |44 and in so doing marks the calling line on its associated nder switch bank, in this instance contact 1 on the nder bank served by wiperY |39; prepares a locking circuit for the lockout relay from ground, open contact ||4, contact |46, through relay H0 to battery;

connects the cut-oit relay to the C lead from which ground was just removed through contact and contact |43; and completes a circuit from ground through contact H3, contact |45, contact |5|, upper Winding of allotter start relay |60 to battery, operating allotter start relay |60.

The function of the allotter is to preselect and assign an. idle finder-connector link for a succeeding `call whenever a call is initiated, and to distribute traffic to the nder-connector links in regular rotation. The allotter consists of twelve relays, nine of which are shown in Fig. l. Each time a. call is initiated, start relay |00 operates, as traced hereinbefore. In operating, relay |30 closes a circuit from ground through Contact IGI, relay |50 to battery, operating relay |50. 'Slow-to-operate relay |50 Yin operating closes a circuit from ground through contacts |52, |33', peg count (PC) meter, not shown, to battery, which meter 4counts the total number of calls for all links. Relay |50 in operating also closes a circuit from ground through contact |53, through a timer start relay, not shown, to battery. The allotter start relay |50 having operated, seizes the preselected idle finder-connector link, the lcircuit for which is from ground through contacts H3, |45, |62, lower winding of relay |00, contacts |63, |13, over conductor H1 Vand through lower winding of impulse relay 240 in Fig. 2 to battery thereon; 'closes contact |64 extending timer #l lead through contacts |33, |33, |34, through timer #i relay |80, to battery thereon. Ground pulses three seconds apart are forthcoming on the timer and 2 leads. If the calling line is not found before the rst ground pulse arrives over timer l, lead relay will operate, holding itself operated from ground through contacts |02, |82, |54, through its winding to battery, closing timer 2 lead through `contact |8|, relay |00 to battery. The nextV ground pulse over timer 2 lead will operate relay |00 through this circuit closing contact |05, opening the holding circuit to relay |80 at Contact |02, and shunting relay |10 from ground through contact |9|, relay |00 lower winding, contact |15, relay 10, contact |16 to ground. Relay |10 falls back and the operating ground from the start relay |60 will seize the next idle Ender-connector link by a circuit from ground through contacts H3, |45, |62, relay |00, contacts |03, |12, 113i, over conductor H8, and impulse relay, such as 240 in a second link, to battery. the seized link has a maximum of six seconds to find the calling line. If unsuccessful after six seconds, the allotter will sequentially allot the next idle link to the task. This cycle may be repeated until the calling line is found. lSubsequent calls will similarly be allotted sequentially untilY all six sequential relays have been used and have fallen back either due to timing or to an open circuit at contact 201, at which time the operating ground of relay |30 will be extended through contacts |12, intermediate ccntacts |12i, contacts |125, through reset relay |00 to battery. Reset relay |00 will then close ground through contacts |02, |03 and |04 and other similar contacts, through the windings of relays |105, |10i, and |10 and other similar relays, the respective conductors H8, busy keys 203, contacts 201, conductors i8', normal bank contacts and wipers 448, interrupter contacts 434 and connector motor magnets 433' (Fig. 4) to battery, operating all sequential relays whose links are not busy. Due to the high resistance of the sequential relays, such as |10, the motor magnets are not operated over these circuits. If all the links are busy, operation of reset relay will close a circuit to the All trunks busy (ATB) relay from ground through contacts |1|, |1|i, |1ls, i0! through ATB relay |30 to battery. Slow-to-operate relay |30 operating In this manner,

will lockitself through its own contact |35 and will close a circuit fromground through contact'l32 through ATB meter, not shown, to battery,` registering an all trunks busy condition. l

If all are busy and another call is attempted, relay |50 will operate closing a circuit from ground thro-ugh contact |52 and contact |34, the latter having been closed by operation of ATB relay |30 as previously set forth, through an overow meter, not shown, to battery, registering thereon the condition Athat additional calls were attempted when all links were busy.

When all links are not busy, operation of reset relay will not operate slow-to-operate ATB relay |30 because its operating circuit is opened at any of the reset contacts |1I, |1Ii, or Ille, before the relay |35 has had sufficient time to operate.

Returning now to the call from subscriber 231 to subscriber 475, it will be `assumed that by means of the allotter hereinbefore described, impulse relay 240 in Fig. 2 has been seized through thecontacts |13`of the iirst idle allotter relay.

Relay 240 operates through its lower winding and closes a circuit to relay 250 from ground through contacts 2||a, 23S, 24|, relay 250 to battery. Relay 250 operates and completes a circuit at contact 255 from ground on the normal contact, N, of the bank of the finder switch served'by wiper |19 through contacts 206, 255, |99, motor magnet |95 to battery. This operates the nder motor magnet |95 which upon releasing by the opening of its own circuit at its interruptor contacts |99, steps the wipers |09, |29, |49 and |69 to the first bank contact. As was previously mentioned, relay |40 had removed ground from the C lead of the calling line, whereas all other lines have their C leads grounded. The motor magnet, |95, therefore, will continue to operate and release, self interrupted over the circuit described immediately above from ground encountered on the finder bank conta-cts of non-calling lines. This sequence will continue until the bank contact of the calling line is reached, which being ungrounded will not permit the motor magnet |95 to step further.

Relay 250 also has prepared a circuitfrom ground through contacts 252, upper winding of iinder switching relay 239, contacts 205, 255,

|99, motor magnet |05 to battery. This winding of relay 200, however, is short circuited during the stepping of motor magnet |95 by the ground encountered on wiper |55 from the grounded bank contacts of non-calling lines. When the nder wiper |69 reaches the calling line, absence of ground thereon allows iinder switching relay 200 to operate through its upper winding in series with motor magnet |95 through the circuit described immediately above. Motor magnet will not operate over this circuit as the current therein is not great enough to permit it to do so `because of the high resistan-ce of relay 200. Relay 200 operates closing its X contact, 2Mb, and locks through its lower winding in a circuit from ground through contacts 252, 2041), 253, lower winding of relay 200 to battery. Finder switching relay i200 now fully operates and opens the circuit to motor magnet |95 by opening Contact 206; closes a circuit to the calling line cut-off relay |20 from ground on contacts 252, 204D, 253, 213, 295, 205, wiper |39, over C lead of calling line,` contacts |43, HI, cut-oir relay |23 to battery; closes a circuit to relay 210 from ground at contacts 252,

204D, 253, 2|3, 296,- 205, 204a, 215|, relay 210 to battery; closes the negative and positive talkingconductors, v--L and +L, of the calling line through the` iinder, to the connector link at contacts 202 and 203; and opens the -circuit to the links associated allotter relay |10 by opening its holding circuit at contact 1201, releasing said allotter relay which then selects the next idle link `for the next call as described hereinbefore.

Cut-off relay |20 operates, closing its X contact |2| rst and locks therethrough over the same circuit from which it was operated except that itnow bypasses contact and |43; opens the operating circuit of line relay |40 at contacts |24 and |25; and closes a circuit to lockout relay |10 from ground through contact |23. Line relay |40 releases andopens contact |45 which breaks the circuit to the allotter start relay and connects the C lead to the conneetor normal, CN, lead through contacts |41 and |2| to maintain this line busy to the connectors. Lockout relay ||0 operates for purposes which will be fully described hereinafter.

When relay 210 operates `as previously described it closes a circuit to upper winding of relay 300 from ground on contacts 216, over conductor 243, contacts 351, 312, 362, relay 390 toV battery; closes a circuit to the lower winding of relay 4|0 from ground on contacts 216, over conductor 243, contact 351, relay M0 to battery; closes `contact 211 to connect the permanent timing start (TS) lead to timing relay 2|0 through contacts 2|5, 235, 211, relay 2|@ to battery to start permanent timing, ,which will be explained also in detail hereinafter; and closes con;-

upper winding of relayill to battery. Relayii'iYY f in operating connects the wipers 441 fand/448 of` connector CS together by closing contact lill.V

Functions of other contacts of operated relays will be described hereinafter in the sequence in Y which their functions appear.

All of the operations hereinbefore ldescribed have takenv place responsive to subscriber #23?. having removed the handset from the cradle.

Having relays H9, 120,240, 250, 209, 210, 390 and 410 now operated, the subscriber hearing dial to-ne begins to dial. All local numbers begin with digits 2, 3, 4 or 5, each designating groups of ten Dialing is accomplished by means of a well v kno-wn iinger dial which sends out a series of impulses o n the return motion of thedial equal to the number selected. Since it was assumed that subscriber 231 is calling subscriber 475 the rst digit dialled is 4. This will alternately open and close thev loop circuit at the dial springs four times and relay 240 the impulse relay, wiil follow the loop impulses alternately restoring and operating. The loop circuit for relay4 240 may be traced from dial tone ground on contact 35lb, through contact 30313, upper winding of impulse relay 240, contact 264, 233, 233, conductor 244,

finder wiper I49, conductor 198, subscriber circuit 23| and back over 4conductor m1, finder wiper |23, conductor 24B, contacts 202, 23I, 232, lower winding of impulse relay 241) to battery. Relay 25B will not fall back during the impulsing because of its copper sleeve making it slow-torelease As relay 240 `falls back with each pulse it closes a pulsing circuit at contact 242 to the minor switch motor magnet 433. This circuit is traced from ground, contacts 2I1Ia, 233, 242, 212, 281, 334, relay 343 to battery and through the same contacts plus contact 325, motor magnet 403 to battery, operating both relay 343 and minor switch motor magnet 498 in parallel. Relay 343 .having a sleeve, is slow-to-release, and will stay operated during the pulsing into the minor switch. The minor switch will step once per pulse and as the digit 4 was dialled, the minor switch will step its wipers four times to contact 4 to operate ypredetermined marking relays.

After the final pulse of the digit, relay 340 restores placing ground on the last and next terminal of minor switch top bank served by wiper 4I9 which are multipled respectively with all even and odd contacts on said bank. This ground is from contacts 21S, conductor 243, contacts 344 to the last Contact or over the same circuit and through additional contact 353 to the next to last contact. This ground as traced to the last contact will be extended through the even contact multiples to contact #4 and thence over wiper 4I9, fourth bank contact, conductor 435, lcontact 3540., back on conductor 433, contact 425a, upper winding of wiper switching and marking relay 423 to battery. Relay 420 operates closing its X contact 421B rst and locks therethrough to ground on spring of contactV 215 over conductor 449 and contact 223D. Wiper switching relay 420, now fully operated switches Vits operating ground from contact #4, over conductor 435, contact 354er., conductor 433, contact 4251), lower winding of marking relay 313 to battery; switches from one wiper set to the other wiper set by closing contacts 421e, 423, and 424D.

Marking relay 313, responsive to digit #4, operates; locks to ground by closing its X contact 313 to ground on conductor 243; closes a circuit to relay 353 from ground, through contact 318ml, minor switch nii-'normal contact (MSDN) 43 I, closed when the minor switch stepped from normal, through relay 350 to battery; marks con nector bank contacts I, 2, 3 and N, served by wiper 441 with ground over leads I, 2, 3, and BN by closing respectively contacts 316, 315er, 314 and 318m; and connects ground through contacts 319, 313 to the R. M. ST. lead to start the ringing machine.

Relay 350 operates and closes a circuit to the minor switch release magnet 40S from ground on lead 243, contacts 358, 3351), 333, 389, 396, 401, minor switch olf-normal contact 432, release magnet 463 to battery; and also closes contact 351m and opens 35lb thereby replacing dial tone and ground to the upper winding of relay 240 with direct ground thereby removing dial tone from the calling subscribers line. Release magnet 439 of the minor switch operates restoring the minor switch wipers to normal and mechanically opens its olf-normal springs 43! and 432, thereby breaking its own circuit at the yofi-normal springs 432. Opening of off normal springs 431 opens the holding circuit for relay 333, previously described. The circuit to relay 353 is also broken upon opening of offnormal springs 431. Relay 3GB restores, closing contact 303a placing ground through the upper winding of pulsing relay 249 to hold the loop intact when relay 350 restores; and opens the circuit to the upper winding of relay 4m by opening contact 3D2. Relay 35D restores and closes a circuit to the lower winding of relay 4I0 from ground on conductor 243 through contacts 351, relay 4H) to battery. Relay 413 remains operated between the opening of its upper winding circuit and closing of the circuit just described to its lower winding because of its slow-to-release sleeve effect.

Returning to where relay 310 operated and marked ground on contacts I, 2, 3, and N of the connector bank served by wiper 441, the ground on contact N closes a circuit through wiper 441, contact 4I1, interruptor contact 434, connector motor magnet 433 to battery. Motor magnet 433 operates, opens its own operating circuit at its interrupter springs 434, stepping wiper 441 to the first bank contact served by wiper 441. This bank contact is grounded also by the marking relay 310 and Wiper 441 extends this ground over the same circuit as above thereby reoperating motor magnet 433 and stepping connector wipers to contact #2. The motor magnet 433 of the connector continues to operate in this manner, self interrupted, until the wipers of the connector switch reach the respective fourth bank contacts, no busying ground being encountered on the fourth contact of the bank served by wiper 441 because of the high resistance of the lower winding of transfer relay 323. As relay 423 has switched wiper sets and as the selected wipers are now standing on the fourth bank contacts thereof, a call to a subscriber in the third tens group, or more exactly, the rst tens group of banks served by wipers 422, 444 and 446, is indicated. A circuit is now completed from ground through contacts 216, conductors 243, lower winding of relay 320, contacts 365, conductor 4, fourth contact of connector bank served by wiper 441, contact 4I1, interrupter contact 434, motor magnet 433 to battery. Transfer relay 320 operates closing contact 32E, transferring the pulsing circuit of relay 240 at this point from the minor switch motor magnet 408 to connector motor magnet 433 by continuing from colltact 334 through Contact 326, over conductor 346, connector motor magnet 433 to battery. Although transfer relay 326 operates at hS time, motor magnet 433 in series with the lower winding thereof will not operate due to the high resistance of said lower winding of relay 320.

The second digit is now dialled and at this time it will be remembered that relays i233, IIB, 24B, 250, 210, 32B, 310 and 420 are operated. The connector wipers are resting on the respective fourth bank contacts. The second digit is the units digit of the subscriber line number. Since it is assumed that the call is to subscriber 415, seven is now selected on the dial. As the dial returns, the loop is opened seven times which will cause impulse relay 243 to fall back seven times. Each time relay 243 restores it closes the connector pulsing circuit from ground on contacts 2IIa, 23B, 242, 212, 281, 334, 323, conductor 34B, connector motor magnet 433 to battery, and over the same circuit through contact 334, relay 340 to battery. Relay 343 operates on the first pulse and being sleeved remains operated during the entire digit pulsing. Relay 34 closes contact 342 closing a holdingvcircuit to transfer relay 320 from ground through contact 342, 32, upper winding of-relay 328 to battery. This assures continued holding of the pulsing circuit to the connectorV motor magnet 433 when the wipers thereof step olf bank contacts #4 whereupon lower winding of relay 32E) loses its operative battery through the motor magnet 433. Connector motor magnet 433 follows the pulses of relay 240 stepping the wipers seven times to contacts #l I, the called line. After the last pulse, relay 240 remains operated over the loop circuit but relay 348 in multiple with motor magnet 433 restores. Release of relay .544 opens the holding circuit to transfer relay 32B at contact 342, restoring relay 328. In restoring, relai7 320 closes contact 325- retransferring the pulsing circuit hereinbefore described again to the minor switch motor magnet 458. The connector switch has its wipers, in this particular call wipers 442, 444 and 446, on the -N, -l-N and CN leads respectively of the called partys line.

The marking arrangement described in con junction with dialing the rst digit 4 of this local call operates similarly for other first digits. For example, digit three would move the minor switch to the third bank contact and ground would be extended therefrom to operate associated marking relays 310 and 380. These relays in operating would mark ground on contacts l, 2, 3, 4, 5, and 6-[4 of connector banks of wiper 441, but wiper switching relay 428 does not opcrate, leaving the calling loop lines closed to connector wipers 4411, 443 and 445. motor magnet 433 steps the wipers self interrupted as explained hereinbefore until thei'lfteenth contact with no busying ground thereon is reached a circuit for the transfer relay 320 isv thereby completed to permit operation of the connector wipers on a subsequent dialled digit. This indicates a call has been marked for the second tens group of the first group of twenty lines. The second digit when dialled will now step the connector wipers to the corresponding Contact in the marked tens group. If the line called was 36, then' the connector will move its wipers responsive to the second digit dialled to contact #2L Having described the marking operations in response to dialing the rst digits 4 and 3 it might be advisable at this point to describe brieiiy the similar marking operations which take place when the first digits 2 and 5 are dialled. For example, digit 2 would step the minor switch to its second bank contact. and ground would be'extended therefrom to operate marking relay 318. This relay then marks the rst, second and third connector switch bank contacts to cause the connector motor magnet to step automatically into engagement with the fourth connector bank contact. The wipers of the connector are now positioned to extend the call to one of the subscriber lines in the iirst tens group when the second digit is dialled. The second digit dialled then operates the connector wipers to connect with the called line. Since wiper switching relay 420 is not operated in response to dialing the first digit 2 the wiper set comprising wipers 44i, 443 and 445 is used. If the line called was line twenty six then the connector wipers would stop in engagement with the tenth set of bank contacts.

In case the digit 5 is dialled for the first Connector 10 digit the minor switch would step to its fth contact and ground would then operate relays 360 and 310 and wiper switching relay .420 to switch wipers. The operation of relays 360 and 374 grounds the rst to fourteenth connector bank contacts accessible to wiper 441 to cause automatic operation of the connector wiper to the fifteenth bank contacts where the circuit is completed for transfer relay 32). In response to the second digit the connector wipers are advanced to the called line in the fourth tens groups. With wiper switching relay 420 operated the other set of wipers comprising wipers 442, 444 and 445 is used to extend the call. If the line called is line iifty six the wipers engage bank contacts 2 l.

In response to dialing the trunk digit "8 marking relay 380 and wiper switching relay 426 are operated in response to the positioning of minor switch in position 8. In response to the operation of relay 380 the connector wipers are advanced to the second or third bank contact, dependent upon the number of the 9 trunks and their location as will be explained more fully hereinafter, and to the rst 8 trunk from where the wipers may be advanced if there is a second 8 trunk and the first 8" trunk is busy.

In response to dialing the trunk digit 9 marking relay 400 and wiper switching relay 420 are operated in response to stepping the minor switch to position 9. The operation of relay 404 causes the connector wipers tor advance to their first bank contacts into engagement with the rst 9 trunk line. If this trunk is busy the connector wipers automatically advance to the second 9 trunk line. If, however, there is only one 9 trunk then the wipers stop on this trunk vregardless of its idle or busy condition.

l The desired line having been selected, the subscriber now dials 5, the third and last digit for selection of the particular ringing code to be applied to the called line. Here again impulse relay 240 follows the dial pulses as the loop is K alternately opened and closed and each time it falls back closes contact 242 to send a ground `pulse over the circuit described in dialing the rst digit to the minor switch motor maget 403. Again relay 340 operates on the first pulse in multiple with the stepping means and because of its sleeve will remain operated during pulsing the entire digit. This circuit has also been described hereinbefore. 'I'he motor magnet 408 follows the impulses from relay 240 over the pulsing circuit previously traced and steps its wipers to the fifth contact. The reoperation of the minor switch closes its off-normal contacts 43! and 432 and in so doing a circuit to relay 350 is closed from ground on contact 3.18a, over conductor BN, minor switch off-normal contact 43l, relay 350 to battery. Relay 34|) releases after the last pulse when its operating circuit is opened at contact 242. In restoring, contact 344 replaces ground from lead 243 onto the top bank of the minor switch served by wiper 4i9 over leads 245 and 247. Relay 350 operates and opens contact 359 removing the ground on the odd contacts of the minor switch top bank leaving the ground immediately hereinbefore described upon the even banks thereof. As relay 340 releases and 350 operatesl the circuitto relay 4|@ is opened at contacts 343 and 357. However, because of its sleeve, relay 410 isslow-to-release and while it is still up, relay 28`is connected to the CN lead of the called line on connector level served by wiper 446 over a path from contact Il through wiper 446. lead CN2, contacts 424D, 4|5, 352, 34|, 306, relay 280 to battery. During this time, before relay 4|0 falls back, the busy test is made. If the called line is busy, it has ground on its CN lead which will appear on the associated bank contact of the connector. Assuming for the moment that the line is busy, this ground will then be extended over the path just described, operating busy relay 280. Relay 280 then locks when relay' 4|0 releases from ground, contacts 333a, 21|, 284, 4|4, 352, 34|, 306, relay 280 battery; at contacts 287, relay 260, opens the circuit to relay 340 and minor switch rotary magnet 408 so that any subsequent dialing will not step the minor switch; tests for a reverting call which will be described hereinafter; returns busy tone to the calling party by closing contact 282 and connects interrupted busy flash to the ilash busy lead from the interrupter source at terminal 438, through contacts 4| 28|, 20|, finder wiper |00 to ilash busy lead FB only in case the calling line is the toll operator at the toll board D Receiving busy tone, the calling party should release the connection by replacing the handset into the cradle.

Assuming now that the line called is idle, the CN lead thereof will have battery thereon from itscut-oi relay and as sufficient time has elapsed during the busy test, relay 450 has released without operating busy relay 280 and a circuit is closed from ground, contacts 3331i, 2li, 285, 225, upper winding of ring through relay 330, conductor 256, contacts 4|6, 42417, lead CNZ, connector wiper 446, bank contact CN lead of called line, through contacts in the called line circuit, such as contact 14| and cut-off relay of called line to battery. Relay 330 operates and locks over a circuit from ground on conductor 243, contacts 33T through lower winding of relay 330 to battery; closes contact 313m preparing a path for the coded ring to go out over the called line loop; closes a path from the pick up lead, PUI, through contact 304, 332, 3|4, upper winding of relay 300 to battery; extends ground through connector wiper 446 to operate the cutol and lockout relays, such as relays |20 and ||0, of the called line, which circuit is from ground, contacts 333i), conductor 256, contacts 4|6, 424D, lead CNZ, connector wiper 44S, CN lead of called line to the called line cut-ori relay, such as |20 to battery. As the cut-off relay of the called line operates, it closes a circuit to the lockout relay as described hereinbefore. Relay 330 further opens the dialing circuits to relay 340 and motor magnets 408 and 433 by opening contact 334 so that any further digits dialled will not move these switches. If an even digit was dialled (instead of an odd digit), relay 336i at contacts 335:1, closes a circuit from the ground on conductor 243, contact 344, conductor 245 to the even contacts of top minor switch bank served by wiper 4|9 through an associated contact 354e of operated relay 350, contact 335e, top winding of relay 320 to battery. As this ground is absent on the odd contacts due to operation of contacts 359, relay 326 will remain normal for odd code digits and operate for even code digits. A ground pulse on the pick up, PUI, lead at the start then completes a circuit to relay 330 from this ground pulse throughcontacts 304, 332, 3 i4, upper winding of relay 300 to battery. Relay 300 operates and locks to ground at the holding ground lead, HG, which cornes from the ringing interrupter and is grounded thereby during each code ringing cycle. This locking circuit is from ground on HG lead through contacts 305, 332, 3 |4, upper winding of relay 300 to battery. Relay 300 in operating closes the circuit for the ringing code through relay 3 I0 and out to the line. The circuit is as follows, from ground on springs of relay 320 through contact 323, 3|2, 33119, 423, over +N2 lead, wiper 444, -l-N lead through the called line circuit and called subscribers ringer, back over -N lead, conta-ct wiper 442, -N2, contacts 42| b, 33m, 3| la, 32|, upper winding of slow-tooperate relay 3|0, contact 308er, conductor 258, wiper 4 0 of minor switch bank, contact l#t5 thereof to code #5 battery connected ringing interrupter lead R5. Ringing current then iiows from this source out over the called subscribers line and through all the ringers on said line. If an even ringing code digit had been dialled, relay 320 would have operated to reverse the ringing and ringing current would be applied to the positive side of the line while the negative side 1s grounded. In either case the ringing current is connected to the line through the upper winding of relay 3|0.

When ringing current is extended to the line through upper winding of relay 3 0 as immediately .hereinbefore described, a circuit for ringback tone is established from ringback tone condenser 369, over contacts 4|2 and 30| to the upper talking conductor. Ringback tone condenser 369 is of the order of .005 microfarad and passes only a small portion of the ringing current for this tone. This tone indicates to the calling party that the called line is being signaled. All ringers on the called line that are connected to the side of the line being signaled will ring, but only the party whose ringing code has been selected answers.

At the end of the first code ringing cycle, ground is momentarily removed from the HG lead. This opens the circuit to relay 300 which restores. Should the called subscriber answer during the interim period, relay 3|0 will operate over the called loop. If the subscriber being called does not answer the rst series of rings, the next ground pulse over PU| lead operates relay 300 again, which again locks to ground on the HG lead and the ringing code is sent again. The cycle is repeated until the called subscriber answers, or the call is abandoned or timed out, the latter to be described later.

Assuming now that subscriber 415 answers, in lifting his handset, a D. C. circuit is closed through the upper winding of relay 310 from ground on springs of relay 320 through contacts 323, 3|2, 33H), 423, connector wiper 444, called subscribers handset 4l5, back through connector wiper 442, contacts 42|b, 33m, 3||a, 32|, top winding of relay 3|0, contact 3080., conductor 25S, wiper 4|8 of minor switch to battery on the battery connected A. C. ringing generator lead R5. Relay 3|0 operates and locks from ground on conductor 243, contact 3|6, lower winding of relay 3|0 to battery. In operating, relay 3|0 opens contact 3| |a removing ringing current from the line; opens the circuit to relay 300 at contact 3|4 and extends the called line loop through to the windings of relay 260 by closing contacts 3| Ib and 3|3. Relay 260 now furnishes talking batteryv to the called line. Relay 310, the ringing cut-01T relay, at contacts 3|9 also opens the ringing machine start ground to stop the ringing machine. Battery feed relay 260 operates and in closing 26| and 233 and opening contacts 262 and 264 reverses battery from relay 240 to the calling line. This battery reversal is for collecting coins if the calling line is a paystation, metering, or to provide supervision-if necessary. Relay 268 also opens the ground on the timer start lead at contact 261 and disconnects the TS lead at contact 266 from relay 2H] so that permanent timing to be described hereinafter will not release the connection. 'Ihe connection is now completed'and the parties may carry on their conversation. Transmission battery is supplied to the calling line from battery on pulsing relay 255 and to the called line from back bridge relay 285.

When the conversation has terminated, Aeither party may sever the connection by hanging up.

If the calling party releases rst, the loop circuit will be opened to impulse relay 225. Relay 255 restores and opens the circuit to relay 252 at contact 255|. Relay 250 restores and opens the circuit to 2li) at contact 25|;v opens circuit to rel-ay 223 at contact 252; and opens theV locking ground to the calling partys cut-off relay |29 at contact 252. Relay`2`l restores and closes a circuit to the minor switch release magnet 469 from ground on spring of relay 2|5 through contacts 2Ha, 2.35, 2'53, 389, 395, 407, minor switch oit-normal contact 432, release magnety 609 to battery; opens the TS lead to relay 2li! at contact 2?, and removes the holding ground from relays Sill, 336, 315 and |20 by opening contact 275. Cut-off relay |20 of the calling line releases which opens the circuit to lockout relay at contact |23 and reconnects the line relay |45 to the line by restoring contacts |24 and |25 to normal. Lockout relay lli! restores. Minor switch release magnet 459 operates and restores the minor switch wipers to normal. Relays SI5,

33B, 3l@ and 526 release. Release of relay 33|! places ground on all bank contacts except the twenty-sixth or norinal'contact, N, of the connector bank served by wiper 458 by closing contact 33S, and opens the cut-off relay of the called lines line circuit by removing the holding ground at contact 333i), which opens and releases the called lines lockout relay. The release of the cut-off relay also reconnects the called partys line to its line relay which operates before the lockout relay releases because of its sleeve. This relocks the lockout relay through line relay contacts, such as contact |46 on the line relay, so that another call cannot be originated or received by the called party until its line relay restores and releases its lockout relay. When the minor switch restores, the circuit to relay 355 is opened at ofi-normal contacts 43| and relay 355 restores. The ground on the connector bank of wiper MS is extended over wiper 468, through interrupter contact 43d, motor magnet 533 to battery. Connector motor magnet 433 operates, breaks its own circuit at its interrupter springs t and moves wiper MS to the next bank Contact, repeating this sequence of operation until the twenty-sixth or normal contact, N,

is reached. Here the connector stops because there is no ground on the normal contact of the level of wiper Q48 with which to further operate the motor magnet. Battery from the connector motor magnet 433 is now connected through wiper dat, contact N, conductor H8, contact 201|, busy key 228 to its associated allotter relay, |70,

in the allotter group. rlhe presence of this battery indicates to the allotter that this link is idle and ready for anotherv call. The inder switch has no home position and remains opposite the former calling line until a new call is assigned to it.

If the called party rreleases `first, its loop lciri4 cuit will be opened to back bridge relay 26|! which restores. In restoring, relay 260 reverses battery again to the callingv party by closing contacts 262 and 2E1land connects the' TS lead through closed contact 265 to relay 2|@ to start permanent timing and to start the timer, to be explained fully hereinafter. f

Release from a busy condition is essentially'the same as for a regular calling party release eX- cept that at this point there are not as many relays operated, and relay 285, the busy relay, is operated. When the calling'party hears busy tone, he opens his loop circuit by replacing his handsetvinto the cradle. Opening of the loop thereby opens the circuit to impulserelay 2E@ which restores. Relay Zet in restoring opens ccntact 25| which opens the circuit to relay 250. Ptelay 252 restores and opens the circuits to the lay 2| at open contact 217; removes locking' ground from relays 375 and 22 by opening contact 215; opens the circuit to busy relay 285 at contact 2li; and places ground on allbank contacts of the connector bank of wiper 648 except the twenty-sixth or normal contact, N, by closing contact N917. Cut-off relay |25 restores and opens the circuit to lockout relay ||D at contact |23. The release magnet operates and restores the minor switch wipers to normal and in so doing opens the oil-normal contacts 43| and 432. Opening of off-normal Contact 43| opens circuit to relay 350 which restores. The ground on connector bank of wiper MS steps the connector motor magnet 33 self interrupted as described hereinbefore until the twenty-sixth bank contact is reached. Battery from the motor magnet is then extended back to the allotter relay to indicate an idle switch available as explained herein'before. Again, the nder switch having no home position remains opposite the former calling line until a new call is assigned to it.

Permanent timing As referred to hereinbefore, the permanent timing feature o this system releases the switch under four different conditions. There are:

a. If the calling station seizes a link and does not dial within two to four minutes. This timing also appliesA to delays in between digits in the dialing.

b. If the calling party does not hang up after receiving busy tone.

c. If the called station does not answer within two to four minutes after the ringing is started.

d. Tf the calling party neglects to hang up after the called party has released.

When the finder-connector link is seized, the following relays are operated; cut-off |20, lockout im, impulse 225, relays 250, 2li), 200, 4|0 and `Biil. The timing cycle starts when relay 210 places ground on the time start lead by closing contact 2'58 and closes the T-S lead through contacts 2|5, 255, 27T and winding of relay 2|!! to battery. As previously described, the timer may also be started by the allotter relays or by another nder-connector link, which makes it possible to get a variable timing cycle. An interrupting mechanism is provided to place a ground pulse on the TS lead and remove ground from the'TR 15 lead every two minutes the ground on TS appearing immediately after its removal from TR. TS is the timer pickup lead and TR the release lead. Should the partially established connection com plete the circuit to lead TS just after ground has been removed from lead TS, there will elapse a two minute interval before TS is again grounded and another two minutes before TR is grounded, totaling four minutes, which is maximum. Should the timing out-connection be completed just as TS is grounded, the time from TS being grounded to TR losing its ground is only two minutes, the minimum. Thus, if the called party has seized the switch and has not attempted to dial, the TS lead will receive a ground pulse and operate timing relay 2id over the circuit hereinbefore described. Relay 2|0 operates and locks to ground from lead 243 through contacts 344, 2|4, 266, 21?, through its winding to battery. In operating, relay 2|6 replaces the holding ground for relay 256 with the ground on the TR lead, the

circuit for which is through contacts 2 |b, 236, 24|, relay 25e to battery. When the ground from the TR lead is removed as previously described, relay 250 is opened. When relay 256 releases, it opens circuits to relays 239 and 210 at contacts 25| and 252. Relay 266 restores and disconnects the line from impulse relay 243 at contacts 292 and 203 as well as opening the previously described circuit to cut-oli relay |20. As the calling party still has the loop circuit completed, his line relay |46 re-operates when relay |23 restores and locks relay H in manner already described in the local connection section. This places ground on the iinder banks from ground on spring of relay |40 through contacts |42, H2, and |43 and onto the C lead and grounds the CN lead at contact |42 so that the line will appear busy on the connector switch banks. Relay 216 restores and opens the circuits to relays 330 and dill at contact 2?6, restoring the link to normal. `Release of relay 263 also extends battery through the connector motor magnet 433 to the allotter relays by closing contact 201. However, the calling line is not able to initiate or receive another call until the line is cleared by release or" the line relay |40 and lockout relay H0, which is accomplished by returning the handset to the cradle.

The same timing out applies during ringing,

except that all relays which are operated during ringing and the minor switch and the connector switch will be released. Reference may be had for this purpose to the description of ringing the called line in the local connection.

Again the same timing out applies when the calling subscriber does not hang up upon the conclusion of the conversation, the release being the same as described for a calling party release in the local connection section hereinbefore described except that the timing pulse releases relay 250 and the calling line is locked out.

Also the same timing out applies when the calling subscriber fails to hang up after receiving busy tone. Here again the release is described in calling party release in the local call except that relay 250 is released by the removal of ground from lead TR rather than the opening of impulse relay 240 and here also, the calling line will be locked out.

And nally, this timing out applies to unanswered reverting calls, which will be discussed immediately hereinafter.

Reverting call by directory number Reverting calls by directory number will be made by stations on a party line in callingA one another. To initiate a call of this character, a station dials the desired directory number and then hangs up. After the third digit has been dialled, the operation of which is the same as described up to that point in the local connection and to which reference here may be had, the following relays are operated: cut-oit relay |20, lockout H6, relay 200, impulse 243, release 250, relays 2'50, 350, 4H), 3360, 319 and possibly 420 depending upon the group called. Also operated are the finder-connector and minor switches. Since in a reverting call, both calling and called parties are on the same line, the cut-off and lockout relays will be common for both parties. When relay 350 operates, it closes a circuit to busy relay 280 from ground originating on the calling partys C lead encountered on the connector bank contact which has been made busy by the calling party himself, from ground at contacts 252, 20412, 253, 2|3, 296, 205, wiper |69, C lead, contacts |2|, |4|, CN lead to the connector bank through the wipers 445 or 446 as the case may be, contacts 424e or b, 4|5, 352, 34|, 306, Winding of busy relay 260 to battery, and also opens the circuit to relay 4|0 at contact 351. Busy relay 280 operates before slow-to-release relay 4|0 restores, and after relay 4|@ restores, relay 280 locks to ground from springs of relay 339 through contacts 333e, 21|, 264, 4|4, 352, 34|, 306, through relay 280 to battery. Busy relay 280 closes contact 282 putting busy tone out on the called line as described in the local call; opens the circuit to the minor switch magnet 463 at contact 201; and prepares a circuit for the lower winding of relay 290.

When the calling station receives busy tone, the handset is replaced onto the cradle. This opens the loop circuit to impulse relay 249 as described in a calling party release in the local call. Relay 240 restores and opens circuit `to relay 250 at contact 24| and also projects ground from spring of relay 2|0 through contacts 2 la, 236, 242, 212, 286, 4|6, 424 to the associated wiper on the connector. Since the relays in the line circuit of the called line are common with those of the calling line in a reverting call, this ground is projected over the CN lead, through contact |4|, winding of cut-off relay |20 to battery` This ground is further extended through contacts |2|, over the C lead, through iinder wipers |69 or |19 as the group of the calling line will determine, contacts 295, 296, 215 to spring of Contact 254 of relay 250. Relay 253 restores and opens the original holding grounds for relays 200 and 210 at contacts 25| and 252, and closes contact 254, completing ground on the spring thereof immediately hereinbeiore traced through the lower winding of relay 290 and 210 to battery. Reverting call relay 290 operates in series with relay 210 and locks from ground through contacts 216 and 294 through upper winding of relay 290 to battery; and closes a holding ground for relay 210 from ground on contact Zlio. through contacts 236, 214, 293, relay 210 to battery; closes ground to the motor start lead at contact 299; closes ground from conductor 243 through contact 291 and lower winding of ring through relay 330 to battery; and opens circuit of relay 200 at contact 296.

Ring through relay 330 operates and locks to ground on lead 243 through contact 331 and if the last digit was an even number, closes a circuit to transfer relay 320 as described in the local call. Relay 330 also connects PUI lead to battery through the upper winding of relay 300 by way of contacts 304, 332 and 3|4, for the ringing code pickuppulse, and v"opens lockingk ground for busy relay 280 at contact 333e. Relay 330 also grounds the connector `Wiper on the Clgbank through con-v tact 333b and over-lead256 and contacts 4|6 and 424s()p that' the cut-01T relay of the line circuitlwill not release when busy relay 280 restores. Relay 280 restores. Ringing begins when the PUI lead is grounded at the beginning of a com plete ringing cycle as explained also in the local call. The ground from the- PIII lead operates relay 300 which locls fromthe holding ground, HG, lead from the ringing'interrupterv duringfthe complete ringing `cycl, e Relayltgl closes ringing current throughgtojthe llin'ethrough the upper winding of 'fringj cutoff relay 3|0 rin the same rfas occurred in the local call. As before; locali-call, if an even ringingcodefthirdf digit isv selected', relay 320 operates and` ringing current goesout through contact1324 onto thev plus sideor' the line whereas if ariodd ringingl digt isfs`elected, relay A32|) will rema" andallow the ringing current to be applred tothenegative side of the line through contact f32|. The ringing code applied, as 'inthe localjvcallgis determined by the 'location of'the minorjswitch wiper 4 I8 Whichi location injturn is` "determined by thev third digit dialled'. "ff'thejcallingstations ringer isconnectedtojthe same side ofjthe `line asftliatjofthe called'V station,` as it would be if the thirdfdigit of-the4 v calling and called `lines were both "odd,j "or' b 'otl'rfjeven; *thel` calling stations ringer will ring'with'that 'ofthe called station, as willall theringersofthe other parties whose ringers are attached tothe same side of the line being rung; lon the other hand, if the calling stationsringer is not connected to the same side o'fftheline as that ofthe called station, the callingvsta'tions ringerwill not ring and as a consequence, the calling l'party in such an instance must allow a reasonable time for the called station to answer. answers and closes the loop for a` direct" current circuit completed through theupper "windingof'Y relay 3 0 from the battery connected interrupteurelay 3 l0 now Operates onethis direct 'current'circuit although it did not operate on the alternating Assuming the called station now Relay 220` operates' and closes 'a circuit from` ground on spring of-relaylflp. through contacts 216, 292, 223, 226, relay 230 and upper winding of. relay 2520 '1to1' batteryl ..Relay.`...2 30` operates# n series .'l'withi. relay; N-:2.2 (l and connef'cts the ground throug-hz'contacts M5, 265-.213.5,:214, '2935-'.

relay 210 to. battery '.Whicknwill' hold .relay 1210. infk ringing current' beforeif'dueto its slow-toperateA f 3 |0- to battery",' opens `thelcircuit 'to relay 300 'at contact yt I 4; removes 'ground 'f roni' the ringingl machine` start (R. M. S; T.) lead *at Contact 3H);

eenneetsfthe'fRoiiU-"iead through contacts an,

, `208,5lower'-wiridi'ng of relay 220 tobattery; dis-l connectsringing current from the line by opening.V "ontactsfSl Iafand 3|2gfswitches connector levels connected .toth'e and .-:N 'leads of., the'line. through toback -bridge` relay 260for2battery feed; 1 arid .connects reverting. call LCRC') tone' tofthe called line lby :closingi'contact 3| I b through condenser 2|`| andcontact=29|b vto indicate .to theA called partythata reverting call is.beingre: ceivedso that the called party will:v not-hang'` up` 2 |.0.f` Approximately. three; to Afour seconds.. after.

RCPU lead islgroundedto operate .relay -.22-0,.the

ground .is removed `from the RCCOI :le'a.dv.. ."-.W this,` ground removed, relay v2 '10. restores holding.. circuits.;` Afor r-Iela'ys; ,2.90, ;.3 |.0,:lv 3202.1 created-"relays-330,.z 300;.3 '|;0;e12 1: I re. moyedmypopening. oticontact Theseg-relaiy allzrelease.. Ground: tronrirelay i2giisgsimil-arly. removed; Relay.3.50.restoresithrough:operlacone' tact 3 61;.; Vllh'errl relays.; 2.30 releases atcircnitz is completed `from ground onfcontact .z-ilgfla.- ofvrelay` 2I0.through?.contactsffZiB,c213,.:300, 396, 401, offnormaLcon-tact432, release magnet 409 to battery, which. magnet-operates, restoring the minor switch to normal. With relays 270, 330 and 220 released, all bank contacts on the connector bank .of wiper 448 are grounded except the twentysixthor normal contact, N, and the connector steps'tothis contact self interruptedA as described.l in the local call until.v it reaches its.Nf.CQI-rtatf.f. where it stops. Release. of relay -330 srmQves om-relay! 20,-1 contact3-:33b... Relay |20 restores,.onenSarut-soi ckoutgrelay.; lm at Contact |2aana.reccnn elayfmo.

the line, nofurther relays operate. "Both parties are onfthe same line and fuse the same line circuit. Talking battery is suppliedybythe line relay |40 lof the line circuit; f

After the conyers'atijonhasgbeen 9o last party tok hangV 11n-opens therlocef Y, line relay |40. Relay |40 restores, opens thee' cuit to lockout relay; 1|0, at 'open contac' andv removes groundrom: f; leaflet. Contact n.42 to.rna1f1: ii1 ev imei-igiene trigger-.infector banks Lockoutzrelay H50 restores'fand -places ground on thefnder; bank'fcontactassociated with the line leady thereto. Thegcircuit is now normal.

n-If thecalling station desires to disconnect the call before-the called station answers, the call-V ing party merely lifts the handset momentarily and then replaces it. The ringing will stop and all operated relays will function as described hereinbefore where the called party tothere-f Verting call answered. Only thelinegandolqg out relays remain operatedandfwhenthe c al ing party hangs up, thQSQP-.stele Las the I?? sf:

If a revertir- 1g ;cal l *v I nad .ai'riril ntansweredA ringing continuesfor apredeterrnined length of time.- The:corlnetion is yautomatically released by theprpermanent timing feature described in thefsectin on .'permanent 1@timing hereinbefore;

' ceptionftha't': atl'that stageinaz vrelays.52.40;'' 250 ffand.; |10:l andreyetirigfrcaiif sreiaggemt operated' operated, is released when relay` 279 restores opening ground thereto at Contact 216.

Trunk calls There are six single-digit switch-through trunks available in this system. These trunks may be arranged into two three-trunk groups or into three trunk groups with a common trunk serving as an overflow trunk for two of the groups. These trunk groups may be reached by dialing 0, 9 or 8 as the trunk digit. This system is readily adaptable to the trunking needs of dierent localities. The ensuing Variations are made possible by Wiring as follows:

a. First group of single-digit, 0, trunks; if only one trunk inA the group is desired, lead A and Al (Fig. 3) are not wired. Ii two trunks are desired in this group, the A lead is wired to the CN connector bank contact of the rst trunk inthe group. If three trunks are to be used the A lead is wired to the CN connector bank l Contact of the rst trunk in the group and lead AI is wired to the CN contact of the second trunk in the group.

b. Second group of single-digit 9 trunks, or

part of second group of three accessed by digit.

9; if only one trunk is used, leads B and Bl (Fig. 4) are not wired. If two trunks are used, lead B is wired to the CN connector bank contact of the first trunk in this group. And if three trunks are used, the B lead is wired to the CN contact of the rst trunk in thisgroup and Bl lead is wired to the CN contact of the second trunk of the instant group. Where the rst and third trunk of this group are used, the B lead is wired to the CN contact of the first trunk of the group and lead Bl is wired to ground.

c. Third trunk group, or part of the second I trunk group accessed by dialing digit 8; if only one trunk of the 9 group was used as the second trunk of the group, the C lead (Fig. 3) is not Wired. 1f only one trunk of the 9 group was used and was the third trunk, the C lead is wired to ground. Where two trunks of the 9 group were used and were the second and third trunks of the group, the C lead is wired to the CN connector bank contact of the second trunk.

A trunking arrangement is shown in Figs. 5 and 6 wherein the second trunk group of three lines is composed of either two 9 trunks and one 8 trunk or one 9 trunk and two 8 trunks. n the first case as shown in Fig. 5 the second trunk in the group is a common overflow trunk for the 9`trunks in the group. Fig. 6 exemplifies a third contact 8 trunk as overflow for the two 9 trunks. Fig. 7 is an arrangement for the last 9 trunk to be common overflow for the other 9 and the 8 trunk.

Assume now that the wiring is such that three trunks are available to digit 0. These trunks appear on bank contacts itl, #2 and #3 of connector levels served by wipers fiel, 943 and 445. When 0 is dialled as the first digit, seizure of an idle finder-connector link through operation of the allotter relays will again be the same as described in the local call. Relays i213, ll, 249, 259, 290, 210, M0 and 309 are operated, impulse relay 249 following the dial interruptions in the calling line loop circuit, closing circuits during restorations to relay 340 and minor switch motor-magnet :108 in multiple, stepping the minor switch wipers to the tenth bank contact in the same manner` as described4 in the local call.

Yits holding circuit at contact 351.

20 Relay 34o releases after the iinal pulse ofthe digit due to open contact 242 in its operating circuit and extends ground to the top ininor switch bank of wiper 419 from conductor 263 through closed contact 344 and over conductor 245 and conductor 241 through contact 359. Wiper 419 extends this ground to the tenth contact on its bank which is connected to 0 marking relay 390 and battery. Marking relay 399 operates over this circuit from ground on the tenth top bank contact of the vminor switch through contacts 356e, relay 399 .to battery. In

Yoperating relay 390 locks to ground on conductor 243 through its own contact 392; closes a circuit to relay 359 from yground through contact 395, over conductor BN, minor switch oft-normal contact 43l, relay 350 to battery; grounds the normal, N, bank contact of wiper Milfrom ground through contact 395 and over conductor BN; closes a circuit from ground on contact .M3 through contact 39|, conductor 439, upper winding of relay 220 to battery; opens the minor switch release circuit at contact 396; connects the A lead to bank contact lof connector level of wiper 441 through contacts 394 and 371; and connectsthe AI lead to bank contact #2 of wiper 44T through contacts 393 and 31519. As stated hereinbefore, the wiring for a three-trunk 0 group provides for the A lead to be wired to CN contact of trunk #l in the group, AI wired to CN of the trunk #2 and CN of trunk #3 is not Wired because it is the last trunk in the group.

Relay 229 operates and locks itself from ground on contact 333e, through contacts 27|, 285, 226, relay 239, upper winding of relay 229 to battery, but short circuits trunking relay 230; opens thev locking circuit to relay 390 at Contact 22?; opens the connector restoring circuit at contact 228; closes a holding circuit from the C lead through lower winding of relay 299 through contact 252 to ground; and connects the upper winding of relay M0 to the pulsing lead 346 by closing con` tacts 222 so that it will stay operated from any pulses into the minor switch motor magnet 408 after relay 359 operates which ordinarily-breaks operates and opensthe lower winding of relay d l at contact 351; removes dial tone from the calling line by opening contact 35th; and closes wiper M5 through contacts 32de, 415, 352, 3M, 30S, busy relay 280 to battery.

The ground on the normal, N contact of connector bank of wiper Il? Ypasses through the wiper drill, contact 4l?, interrupter contact 43d, connector motor magnett33 to'battery.` The motor magnet operates and steps its wipers to contact #L The first trunk of the 0 group is wired to bank contacts #l of wipers Ml, 343 and 445. If this trunk is busy, ground from the #l CN bank contact will appear on lead A over contacts 394, 3H to ground contact of #I 'of bank of wiper 441. rIhis ground is extended from wiper M1, contacts M1933, 222 tov hold relay H9 through its upper winding. The motor magnet 433 operates from this same ground and steps the wipers of the connector to contact #2. If this trunk is busy also', ground on the #2 CN contact willv extend from the #2 bank contact to Al and over contacts 393, 3l5b, #2 minor switch contact, wiper 4l and will act as described for contact #l and hold relay M3 and step the connector motor magnet moving the connector wipers to contact #'3;l If the last trunk, too, is busy, the motor magnet will not step'further since the CN contact Relay 350V through contacts 424m, 4I5, 35,2, 34|, 306, relay`280 y to battery and return busy tone to thevcalling line through closed contact 282. Relay 4|0 restores and locks busy relay 280from ground through contact 333e, 21|, 284, 4|4, 352,` 34|, 306, relay 280 to battery. The calling station continues to receive busy tone and holds the connection until he hangs up or until permanent timing releases the connection as described.` i

If one of the called trunks is idle,there will be no ground on the CN lead thereof to operate busy relay 280 or to step the connectorwipers, and when relay-L 410, restores, the shorttcircuiting of trunk relay 230 is removed-by'opening of ground at contact 4|3. Trunk vrelay 230 operatesA in series with relay 220 and locks to ground at contact 33313` through contacts' 21|, 285 and 226.1- In operating, relay 230`closes contacts 232, .234 fand 231 extending the plus and minus lines and vC lead through to connector levels of wipers 44|, 443 and 445. This completes the loop to the next succeeding switch. A trunk repeater yseized over this loop from the calling stationsends groundback over the CN lead. This ground will hold relays |20, 220, 230-and 200 operated, theciruit is traced from ground on CN and wiper i445, through contacts 424a, 4|6, conductor 256, contacts 336, 238, 226,for relays 230 and 220 to battery' andY-from contact 336' on through vcontacts 231, 204a, 205, 296, 2|3, for relay 200 to battery; and from contact 2040i, wiper |69C= lead, contacts |2|, relay |20 to battery. Relay |20 holds relay I operated from ground through contact |23. At contact 236 relay 230 opens the circuit to slow-to-release relay 250. Extension of the and lines through to the repeater disconnects call'is furnished back to the calling station bythe c f I to Since the switch ahead is'held up over the call-'-` succeeding trunk repeater switch.

ing lines loop just described, release is controlled by the calling station. When the calling station disconnects, the loop is openv to'the trunk repeater which restores, removing ground fromr the CN lead. Removal of this ground causes the operated relays 200, 220, 230, and to release. Release of relay 230 closes a circuit to the minor switch release magnet 469 from ground through contacts 2| la, 236, 213, 389, 396, 401, olf-normal contact 432, release magnet 409 to battery, operating the release magnet which restores the minor switch wipers. Release/ of relay 220 closes contact 228 which places ground ,from contact 2191), continuing through contact339'to al1 contacts on connector bank of wiper 448 except the normal contact N. Wiper 448 extends this ground to connector motor magnet433 through' nector motor magnet ,cannotA operate again.

Battery from the motor magnetlnow vappears.v afi-.1175

assassin the associated. allotter` relay of the |10 series and operates such relay when the reset relay |00next operates, referencebeing had to that portionof thelocal call hereinbefore describing the *operation of the allotter. Since the nder switch has no yhome position-it remains in its lastoperated position until assigned to anew call. The finderconnector link is now'at normal and ready for the next call. Y Dialing v9,trunks; one, two or, three trunks may be accessed byv dialing digit "9 as the rst digit. These trunks may appear on contacts #L #2 and #3 ofconnector banks of wipers 442, 444 and 446. Reference Was made hereinbefore in regard to the possible connections of trunks.

' Thev operationv of the equipment is the same forI dialing. "9 as for dialing 0 and reference may be had to the description thereof with exception that when, the minor switch steps to the` ninth contact responsive to the dial pulses,v relay` 400 operates from the ground on minor switch con-V` tact 9 of wiper 4|9.throug h relay 400 to battery. Inoperatingrelay 400 closes ground from conductor 243 through'v contacts 402 and 421a, upper winding of relay 420 to battery operating relay 420. Relay 400 locks to ground ,onconductor 243 through its contact .403 and 4relay 420 locks,4

through contact 421D and conductor 449, contact 229b to ground at contact 216; Relay 420 fully operates and closes contacts 42|b, 423 and 424b. switching the outgoing normal leads to connector bank level ofwipers442, 444 and 446 respectively.

Relay 400 also closes contacts 404 and 405 permitting leads Band BI to be used as control normal leads for the rst two trunks instead of leads A and Al.

hunting occursfupon encountering busy on the iirst trunk in the same manner as described fo Dialing 8 trunks: one or two trunks may be reached by dialing "8 as the first digit. :These trunks may appear on contacts #2 and #3 of connector banks of wipers 442, 444 and 446 yas'described hereinbefore. for dialing 8 as for dialing 9 and reference may be had to the description thereof supra with the exception that the marking relay 380 operates from ground on'minor switch contact #8 of wiper bank 4| 9, through contact 35511, relay 380 to bat# tery instead of relay 400. Relay 3180 locks to ground on conductor 243 through its X contact 384 and fully operated closes contact 385 connecting the C terminal through contact 3151i to contact #2 of connector bank of wiper 441 which is then used as the control normal lead therefore.

Relay 380 at contacts 386 by Way of contacts 311 grounds the #I connector bank contact accessible to wiper 441 to cause the connector wipers to step to the second set of bank contacts from where the vide trunks or trunk groups in addition to the six trunks available on the single digit basis.v Theconnector bank contacts assigned to the twodigit trunks are the first contacts in thefourth tens group, accessed by dialing the first digit ,5. As many contacts may be used for two-digit ltrunks as desired,k upv to tentrunks.. A.However Lead B is connected to contact #l ofwiper 441s bank through contacts 405 and 311 The operationis the samev available inthe fourth tens group.Y

Irfy only one trunk per two-digit group isv desired, the Y'lead off of Vthelower vwindingof relay 42% (Figfel'fis wired to the proper-contact on ,con-` nector'bank of "wiper T441# For example, if only twov single-trunk trunk groups are desired in these tWO groups, leadY is Wired to the contact I6 and l'll'off wiper4`41s"bank. I'f three single-trunk trunk'groups4 areY desiredylead Y is wired to contactsfl, l1 and I8' of said bank. The first group islthenaccessedby dialing 5l, the second 52 and soton, Iye indicating the fourth tens group in which'the two-digit trunks fall and l or 2 desighating' the rst or second trunk group therein and soonf all of which will be more fully described hereinafter'.

If indre than one two-digittrunk per group is desired, lead X on of the lower winding of relay 420 is Wired to all bank contacts of wiper 441 representing trunks, except the last trunk in each group. This is so that the switch will stop'at'the end of a group when trunk hunting to be described in detail hereinafter.` For example, if two-digit trunk groups are desired, the first have ing three trunks and the Vsecond having:v two trunks the X lead is-connected `to bank contacts i6 and I1 for the first group of three trunks, and to contact IS for the. second group of two trunks. Here again the X lead is used because of multiple trunk groupsand the last contact in each group is leftunwired for trunk'hunting purposes.

' In niaking a two-digit trunk call seizure of the lnder-connector link-and dialing the iirst and second digits is "the same;` as described in the local call. Itfwillghe"r'ernernb'er-ed that inv response to dialin'gjthegfirstldigit 5, marking relays 3S@ and 310 and wiper! switching relay 429 are operated. When relay340 restores after the last pulse of the second'cligit', the circuit to relay 300 is opened at *contact-343' and ground is closed from conductor 243 :through Kupper winding of relay '385. contacts 38'2a,f328,l 428 to the X lead or from contact 428 through' lower non-inductive wind ing of relay 420to the Y lead. Wiper del will then extend. this ground from either X or Y wiringthrough contact dll and interrupter contact`434 Ythrough connector motor magnet 33 to battery. Relay 3BG operates but motor magnet 433 doesriot since the current is insucient for the later. tooper'ate, and locks to ground on conductor '243' through its X contact 384. New fully operated, relay 3853 opens its energizing circuit at contact' 38211, and completes circuits from ground' jat contact 413 through contact 381, conductor`439, upper winding of relay 22e to battery and vfrom ground through contacts 38? 'and 3521, relay to battery. Relay 22e operates and connects the upper winding of relay 4m through contact 222 to the connector pulsing circuit insuring the operation of relay di() from any iinpulsesv intothe connector motor magnet after operation 'of relay 360.; Vand completes a locking'V circuit for relay d2?) from ground through conm tact 229:1 ,of `relay 22d, over conductor dt'contact d2-1b, upper winding of relay i253 to battery,V

' lay 250 at contact 24|.

the'localcall. Relay All releases after a mo- Inentfand assuming that the first directory listed trunk is idlesothat busy relayl 28e is not operated, opens Contact "411 'separating'wipers 441 and dat, and by removing directground from the upper fwindingof lrelay'22ll'a't o'pen'contact 413 re'moves-thefshort-on trunk relay 230. Relay 23Doperates -i'n-s'eries with relay 22d and locks tofground on spring of relay 33@ through contacts 333e, 21|, 285 and 225; opens the circuit to sloW-to-release relay 25E-at contacts 235; prepares -aholding circuitifor relay 22@ and itself by .closing contact 238ffrorn the CN llead of theV connector'through contacts 42th, die, 23S and 226 through said relays to battery; extends the -1- and and C leads to the succeeding'trunkcircuit Vby closing contacts 232, 234 and231 as described hereinbefore; and in opening. contacts 23| and 233 opens the operating circuit of relay 2&0. The; loop, circuit from.. the 'calling subscribers phone-through the lnder-connector link seizes1the trunk vcircuit connected to this switch.' 'Seizurefo'f the trunk' circuit extends ground back; overt-he CN lead of the connector switchV fory holding purposes. rhe holding' circuit through the link has been traced hereinbefore.` Relay 245i ,releases and further opens re- Relay 2552' restores after anA interyaland opens relay 21@ at contacts 254 and. 252 and leaves relayI held operated through its holding circuit which is from ground on theconnector C lead from the succeeding trunk lcircuit,through wiper dltrcontacts :32th, 1HE;conductor,256,contacts 336, 23,12B6a,25, 256, 224, lower windingl-rof relay 263 to battery.l Relay 229 restores andfopens circuits-to relay 366, 310 and 38D atcontact 21%,.. Relay Stil restores and opens the circuit to relay 359 at contact 381,' and removes the ground from the motor start lead at contact 368.l Relay 31E) restores and removes ground .from.the normal contact N of connectorwip'er 441 .atv contact 318e. Relay 330 restores@ .,Duringzthe'trunk call,` onlyerelays MB, 125, ZC-5, 2520 2313v and 420 .areoperated Transmission battery is furnished back over the loop from the succeeding trunk circuit. The succeeding trunk circuit holds allthe above mentioned relaysoperated.' The calling subscriber has direct control of the succeeding trunk circuit and may release thev connection lby hanging up thereby removing the holdingfgroundextending back rolnthe trunk Circuit- L Assuming-now thatjthe busytest has just been rnade duringtheV interval that relay 4 I ll holds up on, its copper sleeve asdescribed hereinbetorejl and the single trunk of this group is busy, 1

ground from the CN lead of the `busy trunk then operates busy relay 238 over the circuit previously described. In operating, relay 23e extends the ground over4 the connector CN lead through con' ta'cts 424b,54l5, 3527, 325, 233, 35229, "2t, 28, lower non-inductive winding or" relay 112i?, Y conductor, bank contact I6, connector Wiper 441, con- Y tact dll, interrupter contact -.!i.3!l through motork magnet 433 to battery'and from interrupter contact 434 over conductor 326, Contact 222 and upper winding of relay l to battery. Motor magnet 433 does not operate .in series with thev Winding and the motor rnagnety just described at Contact 415,' perinitting busy relay 289 to lock to ground on contact 333e over a circuit described 25 for such purpose in the local call. Relay 220 releases due to the opening of its circuit at open contact 4I3. Busy relay 280 closes contact 282 sending busy tone out over the calling loop also describedin the local call.

Trunk hunting will occur where there is more than one trunk in a two-digit directory listed trunk group; and as explained hereinbefore, multiple trunk groups necessitate the use of the X wiring. All but the last trunk in the group has its connector bank contact on bank ofwiper 441 connected through X wiring, contacts 428, 328, 382D to the spring of contact 283 on relay 280. If a trunk is busy, ground on the CN lead will operate busy relay 280 over the busy operating cir cuit described hereinbefore.

Assuming that the first trunk of the multiple two-digit trunk group is busy, busy relay 280 operates before relay 4I0 releases and extends its operating ground through contacts 283, 3821), 328,

428-, Sover! X vwiring-,'- connectorl wiper! '441- andi-engaged bank contact, contact 4I'1and434 through motor magnet 433 to battery and'also from in- Aterrilpter Contact 434 over conductor '346, contact 222, upper winding of relay 4I0 to battery, connecting the motor magnet and relay 4I0 in parallel. This direct ground holds relay 4I0 op- 'erated-and steps the connector motor magnet to the next trunk in the group. This busy test and movement of wipers continues until an idle trunk is found or the last trunk in the group is reached.

When an idle trunk is found, the nder-connectorlink switches through in the same manner as described hereinbefore for an idle single trunk group.

Assuming that 'all trunksof the multiple trunk .group are busy, Vand remembering that the last trunk in the groupis not wired to its respective bank contact of connector wiper 441, when the wiper has stepped to thislast busy trunk in the group, and the busy test is made, rrelay 280 operates but the motor magnet cannot step further since there isno ground circuit therefor. Relay 280 opens the minor switch pulsing circuit at contact 281 and-closes contact 282 putting busy tone out on the line as described hereinbefore. Relay 4I 0 restores and opens relay 220 at contact 4I3 and busy relay 280 vlocks itself to ground at contact 333:1, described hereinbefore. yBusy tone will remain on the calling stations line until the calling-party releases or is timed out.

Incoming toll trunks also have access to these switches. The toll trunks terminate in regular line circuits. An incoming toll call loperates the sameas a local call except that if the line'called is busy, sixty interruptions-per minute flash busy is provided. This goes out on theY toll trunk through finder banksl of wipers |09 or i I9 and out over a fth conductor FB. `This flash busy is closed when relay 200 is operated closing contact I and busy relay 280 is operated closing contact 28 I, and relay 4 I 0 has released after the busy test as described hereinbefore and closes contact 4I I putting the sixty IPM flash busy out on the FB conductor to the toll operator.

Similarly, the free service trunks from nearby communities have access to these links. These trunks terminate on line circuits just as do the subscriber lines and toll trunks. The operation hereof is the same as for local subscriber lines.

Paystation originated calls operate the equipvment the same as a local subscriber call except that paystation, PS, tone is placed on the Cl lead through a condenser H15. On calls to a toll operator, subsequent equipment will transfer this tone Y 26 to the loop. In this forty line arrangement, equipment for two paystations is provided. The equipment is inserted by jumpering to any two subscriber lines desired.

Overflow trunks The trunking arrangement in this exchange provides for overflow trunks under certain Wiring conditions as well as providing for a common overow trunk to serve two groups of trunks under otherfwiring conditions. n

A common overflow trunk for an 8 trunk and for af9 trunk isset out in Fig. 7 in which the 'third trunk,` a 9 trunk, is common thereto. In this particular arrangement, the B lead is wiredto the CN contact #I of wiper 446 which is connected to a #s trunk, the BI lead is wired to ground, and the C. lead is wired to the CN contact #2 to which an 8 trunk is connected. On the third CN contact of4 wiper 446. to which,isiconnected a 9 trunkis the common trunk Aandvis not wired. In such an arrangement, if 9? is dialled as the first digit, relays 400 and 420 operate, reference being had to the circuitsdescribed in the trunking'section. Ground en .the normal, N, contact of wiper 441 steps `the connector wipers to the first -bank contact in the same manner as described in the trunking section. The busy test is then made and if the 9 trunk is busy, ground onits CN bank contact which is wired to the B lead will appear'k on contact #I of connector bankof wiper 441 and step the connector wipers to the nextbankcontact Ato which the 8 trunk has been connected. However, since the BI lead has been wiredto ground, this ground will appear on the secondcontact of wiper 441 through contacts 404 and 31575 causing the connector motor magnet to automatically step the wipers to the third contact to which a 9 trunk is connected. Thisgtrunk is then the overflow for the first 9 trunk. If the digit 8 is dialled underthis arrangement, relays 380 and 420 operate and the connector motor magnet steps the wiper 441 from ground on normal contact N of wiper441, to the rst bank Contact as describedk in the section onfltrunking. Sincer ground appears yon the first bank contactl of wiper 441 through contacts 386 and 311, the motor magnet will step the wipers to the second bank contact to which the 8 trunk is connected. The busy test is now made and assuming this trunk to be busy, ground on 'the CN contact thereof because of the wiring described above appears on the C lead and through contacts 385 and 315D appears on the second bank contact of wiper 441. This steps the connector wipers to the third contact which is connected to the 9 overflow trunk. The 9 trunk on the third bank Contact is therefore ,common to the 8 and 9 trunk groups lproviding overflow therefore when wired under the conditions specified.

Two combinations of overflow trunks are also shown in Figs. 5 and 6. In both examples, the "8 trunk is overflow for a 9 trunk call. In Fig.

5, the conditions are that B` lead be wired to thev #I CN contact of connector wiper 446 to which is connected a #9 trunk and the #2 CN contact to which is connected an 8 trunk is wired to the C lead.l The third CN contact, also an 8 trunk, is unwired. As described hereinbefore, when 9 is dialled and marking relays '400 and 420 operate, the wiper 441 steps to the rst contact from the ground on normal contact, N. Thebusy test is made and assuming it to be busy, ground from Janin-Ace 2?. the.'CN,"lea'd of vthebusy trunk.4 is lextended over the wiring: tothe .B ileadf through Acontacts WE and '-311 to the' first bank vcontact of wiper 441, stepping the connector wipers from' thisfgrcund to the second bank contact, an 8 trunk. The wipers will remain'on this contact and step no further, even though it is busy, since contact 385 "is open, its relay,not'beingresponsive'te a dialled WQidigit. This 8,.trunk i's therefore anlover-V `lfio'wfor the 9 trunk. "Figjd shows any '8 over-` ow trunk for a group of two 9 trunks?. Assuming the both 9 trunks to be busyjgr'ound from their respective CN leads through the B lead and 'then the BI lead -and contacts 405 and 604 respectively, which vclose responsive to a dialled 9 A digitQWillcause' the connector to step its Wipers vto the third ':or ita'ci', an"8 trunk, for overflow.

Azam checking The instant system `also provides 'testing means 'for alarms by'dialing of the'si'ngledigit 7 from 'a distant cnice. The circuit is seized exactly as -describedin Ythelocal ,call sectionr' Whenthe --frh'i-nor switch *movesits yvi'persi to the seventh "'cntact, and relay 340 freleases, Y- ground from conductor 24T 'connected'through `contacts 35e V`v`fanti-i344 to'fgrcund' on' conductor 243 appears on the seventh contact 'of minor yswitch-top bank `of wiper M9 and is extended rby wiper Hover conductor 45| through lower winding or relay -360 to battery. Relay 360 operates and locks to vfg'ro'uild on conductor 243 through contact 363, `Vv`-fllt'nver*winding to' battery Relay 369 closes motor A"start leadl toground throughycontacts'SS and `3|8b"to "start the interrupter" and alarm equipment,"andfcloses theralarm lead through contact 231|', 'condenser 391, 'and contacts 36 IV through to the calling line'ortrunk.' `If a two-ring signal is heard; 'n'o'alarms are present.` 'Absence of such signal indicates 'an alarm is present. This vtest permits determination to the existence cf an alarm condition at the unattended exchange by the wire chief at the distant attended exchange. Having described my invention in detai 1, what laim and desire to be `protected by issuance of tters Patent of the United States is.

, subscribe lines, aconnector switch having acessltsaidlpluralityfoi,groups of lines iorl extendingiconnections ari-auxiliary switch having va plurality' offbank cnta'ctsa'nd a Wiper therefor, lmeanvsincludingan operating circuit to step said a A xiliaryswitchresponsive 'to agroup of impulses cuit to operate said auxiliary-switch responsive to a group of impulses transmitted thereto for positioning'said Wiper onthe'contact corresponding 'to' the vnumber pf impulses transmitted,- operating circuits responsive to jthe positioning of said wiper on different ones of said contacts for operating said marking relays, means for selecting one of said sets of wipers over which the'connection is to be completed, and marking circuits controlled by said marking relays so operated for marking said connector in accordance with the groupof)subscriber-lines linto which the connection is toterrninate.-.` a l Y f 3.- In a'telephone system as claimed inclaim'Z, including means operatedresponsive to the ,positioning of said auxiliary switch wiper aftergthe stepping thereof and 'after said marking has been accomplished for -restoring said auxiliary-switch, and=circuit-Y means effective in'responseY to la second -group Aof-irnpulses ior4 directively stepping saidv connector Wiper sets to select aline in said marked group of lines. v Y f y- 4. In a telephone system vas claimed in claim v2, including means operated responsive to thevpositioning of said auxiliary switch wiper and after said marking has been accomplished for restoring said auxiliary switch, means responsive to said restoration of said auxiliary switch for disa'bling said operating circuit of said auxiliary Switch, means responsive to a second. received group of impulses' for vdirec'tivelyY :stepping said connector wiper sets toselectaline insaid marked group oflines, meansfresponsiveeto the terminationv of lsaid second :group of vimpulses for reestablishing said disabled operating circuit of said auxiliary' switch, said ref-established operating circuit 'oi saidf'auxiliary switchjresponsive to a third re-ceived group of impulses for 'reo'pei'ating said auxiliary switch to selecty thedesired ringing code for said iconr'iection'.` L

5. In -atelephone system, a `connector switch having a control wiper, aline wiper and'respective control and line contact banks, the first and certain progressively succeeding contacts of said -control bank forming single-contact groups, certain contacts of said line lbank forming a multicontact group, said multi-contact group of said line bank immediately succeeding the last singlecontact group of said control bank in the order of selection, an yauxiliary switch having a marking.

wiper andan associated marking contact bank.

frelays connected to said marking bank contacts,

"fltian'smiaear einem posiuonmgsaid wiper on the,.contactfcorresponding to thenumber of irnpulses transmitted; ra 'plurality'. of. marking relays each associatedl with certain ofsaid contacts, operating circuits responsive to the positioning 'of said wiper on diderent ones-of said'cont'acts for pei-ating said marking relays associated l,with

aidd-iierent ones of said contacts, .a group of 'ectorfbank terminals for each group o'f lines,

w o'ntrolle'd by said marking relays so yperatedp,for'ma'rkingr all said connector bank ,terrhinaispreceding' the groupof subscriberlines nto' which said'connection is ytoterr'ninate4 f/2"ln a telephone system, a connector having a luralityof sets`o`f wipers, ai plurality of groups of subscriber lines accessible to said sets-of wipers ffor extending connectionstheretoj an lauxiliary witchhaving a-w-iper and a plurality of contacts;

plurality o'ffmarking relays each associated with 2-crtair'r of' saidv contacts, means including :a cir-f -means including a circuit do-operate said-auxiliary 'vswitchresponsiveto a received fse'ries of ii'npulses for 'positioning said'- marking "wiper on the' marking bank Contact' corresponding to the number 'of -received impulses, an operating circuit 'responsive to the" positioning of said marking wiper on one of said marking bank contacts for operating one of saidrelays'circuits controlled by said operated relay for connecting markingV potential to al1 but the last of the single-contact groups of said control bank, positioning means controlled by 'said I'operated relay for positioning said'control and line wipers on the nrstj' contacts ofgsai-dsrespective banks, said positioningnieans responsive to said control wiperl contacting s aid' marking potential on the first contact of said control? bank -for posiftioning said controlA and-line Vwipers on the second contacts of said respective banks, said positioning means responsive to said control Wiper progressively contacting vsaid marking potential on said ze' banks -succeeding said second'contacts "until said control wipercontacts, 'said unmarked singlecontact group of said control bank and said line wiper reaches the contact of said line bank immediately preceding "sai'd multi-contact group of said lineba-nk', ls'aidposition'ing means ineffective to furthermove said lin and control wiper-s when said control wiper contacts said unmarked singlecoritact group, whe'i'bysaid line wiper is left engaged with said o'ne'contactof the line' bank immediately preceding said multi-contact group of contacts.

6. A connector switch such as claimed in claim 5 including means eiective after said wipers stop on said unmarked contact group for -causing a second received series of impulses to operate said positioning means, said positioning means operated responsive to said second series of impulses to advance said line wiper from said unmarked contact group to a contact in said multi-contact group of said line bank, according to the number of impulses in said second series.

7. In a telephone system, a connector having a plurality of sets of wipers, an additional control wiper, a plurality of associated contact-banks and a magnet, a plurality of groups of lines connected to certain of the bank contacts associated with said sets of wipers, the bank contacts associated with said control wiper being unmarked, an

auxiliary switch having bank contacts, a wiper and a'magnet, a circuit including an impulsing relay operated responsive to a received series of impulses for operating said auxiliary switch magnet to advance said auxiliary switch Wiper to one of said auxiliary switch bank contacts, relays, means including one of said relays operated responsive to said positioning of said auxiliary switch wiper after said -advancement for selecting the set of connector wipers over which the connection is to be completed, means including another of said relays operated responsive to said operation of said one relay for marking a plurality of the contacts of the bank 'associated with said control wiper in accordance with the value of said received series of impulses, means controlled by said operation of said other relay for advancing said control wiper and said selected set of connector wipers as a unit to cause said control wiper to connect with the rst of said marked contacts, said advancing means responsive to said control wiper connecting with said first marked contact for further advancing said control Wiper and said selected set of connector wipers to cause said control wiper to connect with the next marked contact, said advancing means responsive to said control wiper progressively connecting with said next marked contact and succeeding marked contacts for progressively advancing said control wiper and said selected set of connector wipers to cause said control'wiper to connect with an unmarked contact immediately following the last marked contact, `and to cause said selected set of -connector wipers to connect with the respective bank contacts immediately preceding the respective contacts associated with the group of lines into which group connection is desired, saidV advancing means ineffective when said control wiper conne-cts with said one unmarked contact, said control wiper remaining on said one unmarked contact and said selected set of -connector wipers on said respective contacts immediately preceding said respective contacts associated with said one group of lines, means including said impulsing relay thereafter ist peratecirspcnsive wia' second "received series of impulses for correspondingly? operatingfsaid connector magnet', 'andm'eans 'responsive to? said operation of saidv connector magnetfor advancing said selected set of connector wipers fromsaid respective contacts immlediately'precedingthe Vrespe-ctive'contacts associatedswith said one' group of lines to the respective contactsr associated with one line of said one group of lines, in accordance with the"value'of said second received series of impulses.

8. In a telephone system, a connector having a plurality of vsets of wipers for extending connections, a groupof trunks accessible to one of said sets of wipers, said group of trunks identified by a single-digit code, an auxiliary switch having a wiper, a magnet and a plurality of contacts, one of said contacts corresponding to said group of trunks, -a circuit including an impulse relay operated responsive to a received series of impulses Y corresponding to the single-digit code of said group of trunks for operating said magnet to cause the positioning of said auxiliary switch wiper on said one contact, a marking relay associated with said one contact, a circuit completed for operating said marking relay in response to said positioning of Said auxiliary switch Wiper, marking circuitsV completed responsive to said operation of said marking relay for marking on said connector at least the rst trunk of said group of trunks, means responsive to said operation of said marking relay for selecting the set of connector wipers having access to said group of trunks, and means responsive to said operation of said marking relay for causing the automatic advancement of said selected set of connector wipers to the marked rst trunk of said group of trunks.

9. The telephone system claimed in claim 8 wherein said marking circuits completed responsive to said operation of said marking relay marks on said connector the first and second trunks of said group of trunks, together with means for busying said marked rst trunk, and means responsive to said selected set of connector wipers contacting said busied marked rst trunk for causing said selected set of connector wipers to be advanced to said marked second trunk.

10. In a telephone system, a connector switch having two sets of wipers for extending connections, a rst group of trunks accessible to one of said sets of wipers, a second group of trunks accessible to'said other set of wipers, each said group of trunks identified by a dierent singledigit code, an auxiliary switch having a Wiper and a plurality of contacts, one of said contacts representing said iirst group of trunks, another of said.

contacts representing said other group of trunks, means including a circuit operated responsive to a received series of impulses corresponding to the single-digit `code o'f either one or the other of said groups of trunks for correspondinglyr positioning said auxiliary switch wiper on said one contact or said other contact according to the value of said received series of impulses, marking relays connected to said one and said other contacts, a circuit completed responsive to vsaid positioning of said auxiliary switch wiper for operating the marking relay connected to said selected contact, marking circuits completed responsive to said operation of said one marking relay for marking on said connector switch the rst trunk of said rst group of trunks or the rst trunk of said second group of trunks according to the N349@ 0f.sai fse1eted Ontatfmeans reSPOnSVe u"1:9 said-eperatn Qfsadone markingrelay for Vselec'ljing thesetr of c onnector switch Wipers hav- ,ngaccess `tofthe,marked group ofl trunks, and means responsive to said operation of said one marking relay for causing the automatic advancement of said selected set of connector switch Wipers to the marked first trunk.

PIER. BAIKER.

- References einen in the4 -nlepf this patent l UNITED ASTATES PATENTS Number 

